To me the biggest problem is the uncertainty of the solar disinfection process – depending on things like: is the water clear, less than the necessary 6 hours in the sun, do people wok in the shade, how is the baby carried, does the sun reach back & front etc. If the process can’t be guaranteed it is of little use, and only risks undoing what has been achieved.

To carry the 40 lbs of water the 6 km described above, means a total walk of 30kms?

Why not use existing technology – groundwater control, the roundabout water pump and the roller water carrier. Then invest the effort in increasing the uptake of oral rehydration treatment for the cases when clean water fails and a child’s life are at risk.

Agree with the general theme of the piece (the best designs are often the most simple), but also with the concerns of Mr. Harcourt – his question “How is the baby carried?” is a brilliant example of the sort of sociocultural ‘externality’ that is often overlooked by the most well-meaning design team. The same sort of disconnect happens when you have pit latrines that children won’t use because they are dark and the drop holes are too big… (so adjust the size of the dropholes and put colorful posters inside). Plus 8l isn’t that much aqua even if the system works perfectly.

With that said, the IDDS and Amy’s group rock. I’m also interested in the small-scale water testing solution.

One additional idea – how about looking at what is the latest and greatest in household sanitation systems? One solution worth a closer look is what Sulabh International has come up with – the twin pit pour-flush latrine. See http://sulabhinternational.org/pg02.htm . I’d love to have the time to research the extent to which this technology or a lightly customized version thereof would be applicable in other parts of the developing world.

Thanks for a very interesting piece.

John Oldfield